Ventricular fibrillation associated with complete right bundle branch block

Abstract

Background: A substantial number of patients with idiopathic ventricular fibrillation (IVF) present with no specific electrocardiographic (ECG) findings.

Objective: To evaluate complete right bundle branch block (RBBB) in patients with IVF.

Methods: Patients with IVF showing complete RBBB were included in the present study. Structural and primary electrical diseases were excluded, and provocation tests were performed to exclude the presence of spastic angina or Brugada syndrome (BrS). The prevalence of complete RBBB and the clinical and ECG parameters were compared either in patients with IVF who did not show RBBB or in the general population and age and sex comparable controls with RBBB.

Results: Of 96 patients with IVF, 9 patients were excluded for the presence of BrS. Of 87 patients studied, 10 (11.5%) patients showed complete RBBB. None had structural heart diseases, BrS, or coronary spasms. The mean age was 44 ± 15 years, and 8 of 10 patients were men. Among the ECG parameters, only the QRS duration was different from that of the other patients with IVF who did not show complete RBBB. Ventricular fibrillation recurred in 3:2 in the form of storms, which were well suppressed by isoproterenol. Complete RBBB was found less often in control subjects (1.37%; P < .0001), and the QRS duration was more prolonged in patients with IVF: 139 ± 10ms vs 150 ± 14ms (P = .0061).

Conclusions: Complete RBBB exists more often in patients with IVF than in controls. A prolonged QRS complex suggests a conduction abnormality. Our findings warrant further investigation of the role of RBBB in the development of arrhythmias in patients with IVF.

Figure 1

A case of Brugada syndrome complicated with complete right bundle branch block (RBBB). The patient is a 69-year-old man (case 11). The electrocardiogram on admission (A) showed complete RBBB; however, a peculiar ST-segment pattern, which was considered to represent Brugada syndrome, was observed on repeated electrocardiographic recordings (B). The patient showed coved-type ST-segment elevation when RBBB resolved spontaneously, as reported elsewhere.

Figure 2

Electrocardiograms of 10 patients with idiopathic ventricular fibrillation with right bundle branch block. A typical complete right bundle branch block pattern showing a late R wave in lead V₁ (cases 1–9) or lead V₂ (case 10) with a prolonged duration of the QRS complex of >120 ms can be observed. Left axis deviation is obvious in cases 7 and 10. J wave-like notches were observed in cases 3, 4, 6, and 8 (arrows) within the QRS complexes.

Figure 3

Ventricular fibrillation (VF) onset and resolution of right bundle branch block (RBBB) during electrophysiological study. A: A 45-year-old man previously diagnosed as idiopathic ventricular fibrillation followed by implantable cardioverter-defibrillator implantation was admitted for a VF storm. The pilsicainide provocation test for both Brugada syndrome and coronary spasm was negative, but his ECG shows a typical pattern of complete RBBB: an R′ wave in lead V₁ and a slurred S wave in lead V₆ and other leads. A premature ventricular beat that originated from the inferobasal region of the right ventricle was repeatedly initiating the VF. B: During electrophysiological study, the degree of RBBB diminished after right ventricular pacing, which revealed J waves in lead I (arrow).

Figure 4

Onset of ventricular fibrillation (VF). A: The patient was case 3. Soon after admission, VF occurred 11 times, initiated by short-coupled premature ventricular complex, and then VF subsided. B: The patient was case 4. VF occurred after admission and recorded on monitor electrocardiogram. The onset of VF was shown in the inset below, which showed premature ventricular complex with short coupling interval.